The present invention is directed to highly functional decholesterolized egg yolks and methods for preparing such yolks, as well as emulsified food products such as food dressings utilizing such highly functional decholesterolized egg yolk products.
Egg yolks provide excellent functional emulsification properties for a variety of food products such as food dressings, and are a necessary or desirable component for many food products such as spoonable and pourable food dressings. The functional emulsification properties of egg yolks are believed to be largely attributable to phosphatides, proteins and lipid/protein complex components of the egg yolk. However, in addition to these components which provide functional emulsifying properties, egg yolks also contain triglyceride fats and are also a source of cholesterol, normally containing over one percent by weight of cholesterol. Because it may be desirable, particularly for persons susceptible to coronary heart disease, to limit dietary cholesterol intake to 250-300 milligrams or less per day, it would be desirable to provide functional egg yolk products in which a predominant (i.e., over 85%) amount of the cholesterol has been removed. However, cholesterol, which is present as free cholesterol, and in the form of cholesterol esters of unsaturated and saturated fatty acids, is very difficult to remove from the other egg yolk components, particularly including the triglycerides and functional phosphatide lipoprotein complexes. Nevertheless, substantial effort has been directed to the development of processes for removal of cholesterol from egg yolk. For example, solvent extraction methods employing solvents such as hexane, ethyl ether, and combinations of acetone/hexane, ethanol/hexane, and isopropanol/hexane have been used in an effort to provide decholesterolized egg yolk products. Oil extraction and supercritical carbon dioxide have also been used or proposed. However, such methods have tended to have limited success for a variety of reasons, such as inadequate cholesterol removal, deleterious effects of processing conditions, development of off-flavors, loss of functionality of the extracted egg yolk product, high equipment or processing cost, and/or undesirability of extraction solvent components retained in the finished products.
Improved methods for processing egg yolks to provide highly functional decholesterolized egg yolk products would be desirable, and it is an object of the present invention to provide such methods, and such functional decholesterolized egg yolk products. It is a further object to provide emulsified food products such as salad dressings containing such highly functional egg yolk products, which are substantially cholesterol-free.
These and other objects will be more apparent from the following detailed description and the accompanying drawings.